Underlays with damp proof membranes or vapour moisture barriers are designed to be laid on concrete sub-floors to provide a damp proof layer to stop moisture rising into the new carpet or wood flooring. Factors to be taken into consideration are the age of the concrete floor (or how much it will have already dried out) and the floor it is on (ground floors have more change of water from the ground penetrating the concrete). Whatever damp proof moisture barrier you require, Flooring Warehouse Direct stocks a wide range of underlays all tradepriced for you.